- A typical LED roofline costs a few dollars a season to run. The same display in incandescent bulbs costs roughly seven times as much.
- ENERGY STAR says certified LED light strings use about 92% less energy than incandescent strings.
- Formula: watts ÷ 1,000 × hours a night × nights × your price per kWh.
- The EIA expects U.S. homes to pay an average of 18.2 cents per kWh in 2026.
The formula
Electricity is billed in kilowatt-hours (kWh). To find what a display costs for the season:
The wattage is printed on the box or the bulb. Your price per kWh is on your electricity bill. If you do not have it to hand, the U.S. Energy Information Administration expects the average American home to pay 18.2 cents per kWh in 2026, up from 17.3 cents in 2025.
Worked examples: a roofline of C9 bulbs
Our assumptions: a traditional incandescent C9 bulb draws about 7 watts; an LED C9 retrofit bulb about 0.96 watts (Christmas Designers' example of 200 LED C9 bulbs drawing 192 watts). Lights run 6 hours a night for 40 nights, at 18.2 cents per kWh.
| Display | Incandescent: power, energy, season cost | LED: power, energy, season cost |
|---|---|---|
| 100 C9 bulbs | 700 W · 168 kWh · $30.58 | 96 W · 23 kWh · $4.19 |
| 150 C9 bulbs | 1,050 W · 252 kWh · $45.86 | 144 W · 35 kWh · $6.29 |
| 250 C9 bulbs | 1,750 W · 420 kWh · $76.44 | 240 W · 58 kWh · $10.48 |
Our arithmetic. Check the wattage on your own bulbs and the rate on your bill.
That lines up with Angi's estimate of $30 to $75 a month to run an incandescent display and $5 to $20 for the LED equivalent – bigger displays, more hours and higher local rates push toward the top of those ranges.
What changes the number
- Hours. A timer set for 6 hours costs less than half of dusk-to-dawn, which can be 13 or 14 hours in December.
- Your rate. Electricity prices vary a lot by state and by plan. Use the number on your bill.
- Extras. Trees, bushes and inflatables add up. Wrapped trees use many more bulbs than a roofline.
- Bulb type. ENERGY STAR says certified LED strings use about 92% less energy and can last up to 10 times longer than incandescent strands.
How many lights can one circuit take?
A standard 15-amp household circuit at 120 volts handles 1,800 watts, and the usual rule is to load it to no more than 80% – about 1,440 watts. That is roughly 200 incandescent C9 bulbs, or well over 1,000 LED C9s. LED displays rarely trip breakers for this reason. See outdoor Christmas light safety for the rest of the electrical checklist.
Should you switch to LED?
The running-cost saving is real but modest – about $40 a season for 150 C9 bulbs in our example – so weigh it against what new LED bulbs would cost you. The stronger reasons are that LEDs run cool, last far longer and let you put far more lights on one circuit. Most professional installers already use commercial-grade LEDs – if you lease, the switch is their problem, not yours.
Keep reading
- C7 vs C9 bulbs
- Outdoor Christmas light safety
- Lease or buy your Christmas lights
- Christmas light installation cost
Sources
- U.S. Energy Information Administration – Short-Term Energy Outlook, electricity – September 2026 edition; read September 22, 2026
- ENERGY STAR – Decorative light strings – read September 22, 2026
- Christmas Designers – How much do LED Christmas lights cost to run? – read September 22, 2026
- Christmas Designers – How many LED Christmas lights can I string together? – read September 22, 2026
- Angi – How much does Christmas light installation cost? – updated May 3, 2026; read September 22, 2026
Written by the Christmas Lights Outdoor Installation editorial team. Figures are dated and linked to their source; national numbers vary by area – confirm with local installers.
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